Heterofunctional Supports in Enzyme Immobilization: From Traditional Immobilization Protocols to Opportunities in Tuning Enzyme Properties

A heterofunctional support for enzyme immobilization may be defined as that which possesses several distinct functionalities on its surface able to interact with a protein. We will focus on those supports in which a final covalent attachment between the enzyme and the support is achieved. Heterofunctionality sometimes has been featured in very old immobilization techniques, even though in many instances it has been overlooked, giving rise to some misunderstandings. In this respect, glutaraldehyde-activated supports are the oldest multifunctional supports. Their matrix has primary amino groups, the hydrophobic glutaraldehyde chain, and can covalently react with the primary amino groups of the enzyme. Thus, immobilization may start (first event of the immobilization) via different causes and may involve different positions of the enzyme surface depending on the activation degree and immobilization conditions. Other “classical” heterofunctional supports are epoxy commercial supports consisting of reactive covalent epoxy groups on a hydrophobic matrix. Immobilization is performed at high ionic strength to permit protein adsorption, so that covalent attachment may take place at a later stage. Starting from these old immobilization techniques, tailor-made heterofunctional supports have been designed to permit a stricter control of the enzyme immobilization process. The requirement is to find conditions where the main covalent reactive moieties may have very low reactivity toward the enzyme. In this Review we will discuss the suitable properties of the groups able to give the covalent attachment (intending a multipoint covalent attachment), and the groups able to produce the first enzyme adsorption on the support. Prospects, limitations, and likely pathways for the evolution (e.g., coupling of site-directed mutagenesis and thiol heterofunctional supports of enzyme immobilization on heterofunctional supports) will be discussed in this Review.

The minimal overlap rule: restrictions on mergers for creditors’ consensus

As it is known, there is no rule satisfying additivity in the complete domain of bankruptcy problems. This paper proposes a notion of partial additivity in this context, to be called μ-additivity. We find out that this property, together with two quite compelling axioms, equal treatment of equals and continuity, identify the minimal overlap rule, introduced by O’Neill (Math. Soc. Sci. 2:345–371, 1982).

Colestase intra-hepática da gravidez

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2014

spotlight europe # 2014/01 — Februar 2014 - Nordafrika zwischen Krise und Konsens = North Africa between crisis and consensus

No abstract.

spotlight europe # 2014/01 — February 2014: North Africa - Crisis and Consensus

The Arabellion is now in its fourth year. There is more freedom today, but less security. There are far more opportunities, but fewer jobs. And there is a patchwork of conflicts. In many places though the Arab world is tentatively moving towards democracy and the social market economy. Although there have been some difficulties along the way, European assistance for the transformation process is moving in the right direction. Still, the EU could certainly do more on the political level.